In recent years, attempts have been begun in the field of virtual reality to provide olfactory information for users. Int'l. Pat. Appl. No. WO/2007/122879, published Jan. 11, 2007, the contents of which are incorporated herein by reference, discloses an odor blender (olfactory display) including component odor gas containers storing component odor gases, pipes connected to the component odor gas containers, solenoid valves disposed on the pipes to be opened and closed to blend the component gases in desired quantities for producing a desired odor.